diff --git a/pkgs/development/python-modules/flask-assets/default.nix b/pkgs/development/python-modules/flask-assets/default.nix
index 7ebfc34103f2bf..6618e130067de5 100644
--- a/pkgs/development/python-modules/flask-assets/default.nix
+++ b/pkgs/development/python-modules/flask-assets/default.nix
@@ -22,22 +22,17 @@ buildPythonPackage rec {
   };
 
   patches = [
+    # On master branch but not in a release.
     (fetchpatch2 {
+      name = "refactor-with-pytest.patch";
       url = "https://github.com/miracle2k/flask-assets/commit/56e06dbb160c165e0289ac97496354786fe3f3fd.patch?full_index=1";
       hash = "sha256-Feo7gHHmHtWRB+3XvlECdU4i5rpyjyKEYEUCuy24rf4=";
     })
   ];
 
-  postPatch = ''
-    substituteInPlace tests/test_integration.py \
-      --replace-fail 'static_path=' 'static_url_path=' \
-      --replace-fail "static_folder = '/'" "static_folder = '/x'" \
-      --replace-fail "'/foo'" "'/x/foo'"
-  '';
+  build-system = [ setuptools ];
 
-  nativeBuildInputs = [ setuptools ];
-
-  propagatedBuildInputs = [
+  dependencies = [
     flask
     webassets
   ];
@@ -46,10 +41,10 @@ buildPythonPackage rec {
 
   pythonImportsCheck = [ "flask_assets" ];
 
-  meta = with lib; {
+  meta = {
     homepage = "https://github.com/miracle2k/flask-assets";
     description = "Asset management for Flask, to compress and merge CSS and Javascript files";
-    license = licenses.bsd2;
-    maintainers = with maintainers; [ abbradar ];
+    license = lib.licenses.bsd2;
+    maintainers = with lib.maintainers; [ abbradar ];
   };
 }